I have a customer complaining that whenever they use their Ntelos cell phones to call to their office,(KX-TA 624), their cell phone has that annoying echo of their own voice. The cellphones don't seem to have the problem when callng elsewhere. I called from my cellphone (Verizon) and the call was clear. I experience this on my cellphone from time to time, but it's random. Calls from wired phones to the office sound okay.
I don't know why cellphones have an echo to begin with, much less why the customer has a specific problem from their "fleet" of 6 or so cellphones phones. I doubt it's the 624, any ideas?

Vernon Hobbs